Former US Army intelligence analyst Chelsea Manning, who served seven years in prison for leaking one of the largest troves of classified documents in the country's history, has been sent to jail for refusing to testify before a grand jury investigating WikiLeaks.

Key points:

Manning says she objects to the secrecy of the grand jury process

The judge says she will remain jailed until she testifies or until the grand jury concludes

Manning previously served seven years of a 35-year military sentence for leaking a trove of documents

US District Judge Claude Hilton ordered Manning to jail for civil contempt of court after a brief hearing in federal court in Alexandria in which Manning confirmed she had no intention of testifying.

She told the judge she "will accept whatever you bring upon me".

Manning has said she objects to the secrecy of the grand jury process and already revealed everything she knows at her court martial.

She said prosecutors had granted her immunity for her testimony, which eliminates her ability to invoke her Fifth Amendment right against self-incrimination.

"I will not participate in a secret process that I morally object to, particularly one that has been used to entrap and persecute activists for protected political speech," she said in a statement released after she was taken into custody.

The judge said she would remain jailed until she testified or until the grand jury concluded its work.

Sheriff pledges to 'ensure her proper care' in jail

Manning's lawyers had asked that she be sent to home confinement instead of the jail because of complications she faced in receiving gender-affirming medical care.

WikiLeaks also has emerged as an important part of special counsel Robert Mueller's investigation into possible Russian meddling into the 2016 presidential election, as investigators focus on whether President Donald Trump's campaign knew Russian hackers were going to provide emails to WikiLeaks stolen from Democratic organisations, including presidential candidate Hillary Clinton's campaign.

But there is no indication that the Alexandria grand jury's investigation of WikiLeaks is related to the Mueller investigation.